Sonia Hermosillo is charged with murder and with child assault causing death for allegedly throwing her baby boy, Noe Medina Jr., from the parking structure at Children’s Hospital of Orange County last August.

At her arraignment in Orange County Superior Court, Jacqueline Goodman, the attorney representing 31-year-old Hermosillo, entered the not guilty pleas but reserved the right to add not guilty by reason of insanity at a later date.

"I believe she is not guilty by reason of her insanity," said Goodman.

Hermosillo of La Habra faces a maximum of 25 years to life in prison and is being held on $1 million bail. A preliminary hearing was set for June 22 in Orange County Superior Court. An Orange County Superior Court judge ruled last month Hermosillo is mentally competent to stand trial. Judge Kaz Makino based the ruling on psychologists' reports on Hermosillo.

Three court-appointed psychologists examined Hermosillo. But they didn’t come to the same conclusions on her competency. One said she was competent, another said she wasn’t competent and the third said results were inconclusive.

Goodman said the third doctor was appointed to break the tie, but did not. She called the decision by Judge Makino "arbitrary."

"At this point, no doctor, besides the one, has found [Hermosillo] competent, except the one," said Goodman. Goodman said Hermosillo has been medicated and is monitored 24 hours a day in a psychiatric unit.

Prosecutors allege Hermosillo tossed the boy from the fourth level of the parking garage then validated her parking ticket and drove away. She returned hours later and was arrested.

Her husband, Noe Medina, said last year his wife suffered from severe postpartum depression. He said she was upset because their son had several medical conditions. Prosecutors say Hermosillo removed a special helmet the child wore to reshape his head before tossing him over the railing.

Prosecutor Scott Simmons told the L.A. Times that the removal of the helmet was proof that Hermosillo "did know what she was doing."

"The comments [by Simmons] reflects a common misunderstanding of mental illness," said Goodman.

Goodman said Hermosillo developed a psychosis break when she was pregnant with the baby boy and had a psychotic break after the baby was born.

"This was a tragedy of epic proportions and it is compounded by the fact that her acute psychosis and post-partum depression was treatable," said Goodman.

Goodman hopes the case will raise awareness about ignoring the dangers of mental illness.

"My own brother died of mental illness, he was schizophrenic, and so this is something that's near and dear to my heart and I'm hoping that with this case there's some awareness that's raised so we can prevent this kind of tragedy in the future," Goodman said.